Keep your Hydro cooler and ice machines clean and free of scale, algae, bacteria and reduce your chlorine use up to 98%.
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STUDIES IN IONIZATION DISINFECTION
Abstract
TITLE: Evidence for the Role of Copper in the Injury Process of Coliform Bacteria in Drinking Water
AUTHORS: Domek MJ, LeChevallier MW, Cameron SC, and McFeters GA
PUBLICATION REF: Applied and Enviromental Microbiology 48: 289-293, 1984
PURPOSE OF STUDY:
Although high concentrations of metals are known to cause injury to coliform bacteria, little is known about these effects at the concentrations of metals commonly found in drinking water. This study investigates the effect of low levels of copper on coliform bacteria, specifically Escherichia coli (E. coli.) cells, in samples of typical drinking water.
MATERIALS AND METHODS:
Copper concentrations were determined by the differential pulse polarographic method in 44 drinking water samples drawn from two drinking systems in which chlorine residuals were low. Oxygen uptake levels were also determined.
RESULTS:
In the 44 samples tested, copper concentrations ranged from a minimum of 0.007 mg/liter to a maximum of 0.540 mg/liter with a mean of 0.117 mg/liter. A concentration of 0.05 mg/liter produced greater than 90% injury to the E. coli population within 2 days and over 99.5% after 5 days. A higher concentration (0.25 mg/liter) caused injury at a faster rate. Increasing temperature also accelerated the rate of copper-induced injury. Copper alone caused as much injury as a mixture of copper, lead, and cadmium.
CONCLUSIONS:
Exposure to copper has been shown to cause damage to E. coli in drinking water. Since copper from both natural and man-made sources may be present in drinking water, the effect of copper on coliform bacteria should be considered when testing public water supplies. Injury due to sublethal amounts of copper can lead to underestimation of the bacterial count when m-Endo agar rather than the more sensitive m-T7 medium is used.
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STUDIES IN IONIZATION DISINFECTION
Abstract
TITLE: Metabolism of Escherichia coli injured by Copper
AUTHORS: Domek MJ, Robbins JE, Anderson ME, and McFeters GA
PUBLICATION REF: Canadian Journal of Microbiology 33: 57-62,1987
PURPOSE OF STUDY:
Based on evidence that the presence of copper in drinking water, which frequently occurs naturally, can cause injury to Escherichia coli (E. coli) and other coliforms, the authors performed experiments to elucidate the physiologic mechanisms responsible of cellular injury.
MATERIALS AND METHODS:
E. coli was isolated from river water and cultured in broth. Washed cells were placed in an inorganic carbon buffer and the pH adjusted. High concentrations of copper were introduced to produce injury to the 95% level. The injured populations were analyzed using a series of tests: oxygen uptake measurements by oxygraph and differential respirometer, nuclear magnetic resonance spectroscopy, gas chromatography, and spectrophotometric respiration measurements.
RESULTS:
As compared to normal cells, short-term oxygen uptake was reduced by 75% in copper-injured cells. Similarly, long-term respirometry experiments showed that the rate of oxygen uptake of the injured cells was approximately 47% of the rate in normal cells.
Nuclear magnetic resonance spectra revealed that the rate of glucose utilization was 64% compared to normal cells. Similar trends were evident in lactate, ethanol, acetate, and glutamine accumulation under both aerobic and anaerobic conditions. The slow utilization of succinate and decreased production of CO2 under aerobic conditions suggested that copper has major effect on the aerobic metabolic function of E. coli.
Copper-injured cells reduced six times greater quantities of 2 (p-iodophenyl) -3- (p-nitrophenyl) -5- phenyltetrazolium chloride (INT) than control cells when NADH was used as a substrate. A comparison of metabolic end products demonstrated marked differences in carbon flow in injured cells.
CONCLUSIONS:
Exposure of E. coli in drinking water to copper produces a variety of injurious effects. The mechanism include decreased oxygen utilization of glucose, and lowered accumulation of metabolic products such as lactate and ethanol. The fact that aerobic succinate was lowered and less glutamine produced suggest that tricarboxylic acid (TCA) activity is also inhibited.
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FILLMAN LABORATORIES - AUG. 30, 1988
Water study with the Agri Ionization Systems, Inc.
On August 22, 1988, a controlled analysis of recreational water using a prototype of a swimming pool, source water from a municipal water treatment plant, a known bacteriological culture, and the Ion-Pure ionization system as the sole disinfectant was undertaken to determine the effectiveness of the Ion-Pure equipment in reducing bacterial levels.
A modified fifty-five (55) gallon aquarium was used as a simulated swimming pool along with a twenty (20) micron filter as a typical swimming pool filter. The Ion-Pure ionization unit was connected to the aquarium.
The bacterial culture used was a mixed population of Escherichia Coli, Staphylococcus Aures, Staphylococcus Epidermidis, and Streptococcus Pyogenes. The bacterial density of this culture was ascertained by the Membrane Filtration Method for Escherichia Coli using M-Endo Broth and a Heterotrophic plate using a Standard Plate Count agar. All bacteriological testing was performed in accordance with Standard Methods for the Examination of Water and Wastewater.
One hundred (100) milliliters of this culture was induced into the tank and allowed to circulate for ten (10) minutes. Bacteriological samples were collected aseptically at intervals of thirty (30), sixty (60), ninety (90), one hundred and twenty (120), and three hundred (300) seconds along with samples tested for pH, Chlorine, and Copper.
One hundred (100) milliliters were used as an aliquot for the Escherichia Coli and Heterotrophic plates. The Escherichia Coli were incubated at 35.0 C +/- 0.5 for twenty-four (24) hours, while the Heterotrophic plates were maintained at the same temperature, but allowed to incubate for forty-eight (48) hours.
The pH meter was calibrated using three (3) known Standards, while a water bath was used for incubation, and it was monitored for three (3) days. Temperatures of the bath were recorded once in the morning and once at night during the days of incubation. This was done in order to assure the proper calibration of the meter, and correct temperature of the incubator. A positive control plate and a negative control plate were run to check the ability of the broth and agar to induce bacteria groth as well as to check on the technique.
The conclusion arrived at by analyzing this data is that after thirty (30) seconds of exposure to the treatment by the Ion-Pure system, the bacterial levels were well within the accepted limits for recreational waters.
Sincerely,
Allan C. Fillman
Laboratory Director/Chemist
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